Scientists working for industrial chemistry firm Carbios have discovered an enzyme which can reportedly break down PET plastics for recycling into food-grade material in hours, rather than weeks.
The discovery of the new PET hydrolase enzyme was reported in the scientific journal Nature, which claims that the enzyme can break down PET plastics into their individual chemical components in as little as ten hours, allowing the creation of new high-quality, food-grade PET packaging.
PET is very difficult to break down, and many thermomechanical recycling processes produce lower-quality plastic which is then used in non-food related products such as clothing and carpets.
According to the journal, the PET hydrolase enzyme can biologically depolymerise 90% of PET polymers in ten hours, a significant upswing from the initial degradation yield of 1% after several weeks when using other enzymes.
The journal stated: “This highly efficient, optimised enzyme outperforms all PET hydrolases reported so far”, including an enzyme from the bacterium Ideonella sakaiensis strain 201-F6, which had generated interest.
Carbios has now formed strategic partnerships with major food and beverage firms including PepsiCo, Nestlé and Suntory to help scale and develop the technology. In a statement, Carbios said that it would conduct a trial in 2021 to test the “industrial and commercial potential” of the process.
If successful, Carbios claims that the proprietory process could represent a “paradigm shift” in the way that PET is recycled, and could pave the way towards a circular economy for plastics.
Saleh Jabarin, professor at The University of Toledo, Ohio and a member of Carbios’ Scientific Committee, said: “It’s a real breakthrough in the recycling and manufacturing of PET.
“Thanks to the innovative technology developed by Carbios, the PET industry will become truly circular, which is the goal for all players in this industry, especially brand-owners, PET producers and our civilization as a whole.”
This development follows on from a similar discovery made in 2018 by scientists from the University of Portsmouth and the US Department of Energy’s National Renewable Energy Laboratory.
These scientists accidentally engineered an enzyme which could digest plastics including PET. Professor John McGeehan at the University of Portsmouth and Dr Gregg Beckham at NREL solved the crystal structure of PETase—a recently discovered enzyme that digests PET— and used this 3D information to understand how it works. During this study, they inadvertently engineered an enzyme that is even better at degrading the plastic than the one that evolved in nature.
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